Manufacture of ferric oxid.



J. GILL. MANUFACTURE OF FERRIG OXID. APPLICATION FILE JAN. 12, 1910.

1,068,321, Patented Nov. 14, 1911.

-aNvEN oR.

JOHN GILL, 0F PENDLETON, ENGLAND.

MANUFACTURE OF FEB/RIC OXID.

Specification of Letters Patent. Patented N V, 14, 1911,

Application filed January 12, 1910. Serial No. 537353.

My invention is based on the fact that calcium carbonate CaCO can be changed into a soluble calcium bicarbonate Ca(HCO3) and in the presence of a solution of ferrous chlorid precipitates the iron contained in the liquor as ferrous carbonate which is capable of being oxidizedi to ferric hydrate.

The invention consists essentially in treating waste or other liquors containing ferrous chlorid lieCl with carbonate of lime and carbon dioxid CO and air toprecipitate ferrous carbonate FeCO and oxidize the precipitate in'to ferric hydrate Fe (OH) 0 and subsequently calcining the ferric Jhydrate to drive off the water and obtain a pure or high class oxid of iron E3 0 The invention will be fully described with reference to the accompanying drawings forming part of the specification which as an example show a diagrammatic elevation Figure 1. and plan'Fig. 2 of plant-suitable for carrying out the process.

In carrying out the invention I take gal vanizers or wire drawer-s1 waste liquor or other liquor containing ferrous chlorid, FeCl and in a suitable tank orvessel mix therewith a quantity of calcium carbonate CaCO the proportion of the latter being determined by the strength of the solution or the amount of the iron contained in the chlorid. To an average sample of Tw. I add 30 lbs of carbonate of lime.' The mixed liquor is run into a suitably constructed decomposer and oxidizer and a mixture of air and carbonic acid gas 00 is blown through it until nearly all the iron is precipitated the liquor during the process being maintained at a high temperature about 180 F and the'time taken averaging about 4 hours.

The dccomposer and oxidizer comprises a closed steam jacketed pan A with a perforated false bottom a and a generator B for carbon-dioxid from which air and CO are blown into the pan A through the bottom a by an air compressor. An agitator C is placed in the pan A to keep the mixture in j a state of agitation during the process of oxidation. The agitator shaft 0 passes through an air tight gland c in the cover of the pan and is rotated by any suitable mechanism. An inlet pipe D is fitted-to the pan below the false bottom and an outlet pipe'D into the top of the pan'and through the latter the spirit, air and gas pass to a con denser E where any steam or vapor they may contain is condensed. The condenser E is connected to the gas generator and air chamber B from which the CO and air are forced to the inlet pipe D, and again through the mixture of bicarbonate of lime and iron chlorid in the pan A.

Two or more pansor vessels A maybe I connected in seriesas shown and the air and carbonic ac d gas forced, through thenr n succession, a' condenser being placed between the pans if found desirable. The carbonic acid gas CO and-air are forced through under pressure and form with the water in the solution carbonic acid (H 605) which decomposes the calcium carbonate CaCO forming bicarbonate of lime (Ca(HC() The solution of calcium bicarbonate being in a solution f ferrous chlorid FeCl at once precipitates the iron as carbonate of iron FeCQ, with the splitting up of carbonic acid gas and water, the nascent CO again forming I-LCO which in turn decomposes the lime precipitating more iron and so on until the operation is contpleted. The ferrous carbonate thus formed oxidizes into ferric hydrate Fe. ,(OH) owing to the presence of the air which is being blown through the mixture, the process of oxidation being quickened by being heated up with steam to about lsO F.

Instead of mixing the liquor containing the ferrous chlorid FeUl with the calcium carbonate 02100 the process may be carried on by separate operations by pumping carbon dioxid CO into water under pressure forming carbonic acid ILCO and then adding the carbonate of lime CaCO producing a solution of Ca(HC() which is run into a pan or vessel containing the ferrouschlorid solution or liquor when a precipitation of ferrous carbonate FeCO takes FeCU ' of lime and at through the mixture place aftier which atm spheric air is blown no combined water of hydration to drive off, tl irough to produce the ferric hydrate to do which requires about 5 hours in tur t ianace at a temperatin-e of about 2000 Far. the following are the reactions: I B my pmcgss I t th same r sults in (Ialcination of Fe. UrI) produces l+e +3 (H 0.

Most chlorid liquors contain manganese as manganese chlorid and during the process some at this is oxidized to manganese oxid which if allowed to remain in the hydrate of iron and calcined would have a deleterious effect on the resulting 'oxid giving it a brownish tint and consequently lowering its value as a pigment. To obviate this I treat the finished hydrates with hydrochloric acid which decomposes any manganese which may be present into manganese chlorid. After settling the manganese chlorids are decanted oil to be further treated for the manufacture of siennas and umbers. I thus obtain. apractically pure ferric hydrate Fe. ,(OI-I) which after washing to remove all soluble sa ts is filtered, dried and calcined in a suitable furnace resulting in the production of a high class or practically pure :lerric oxid Fe O of from 97% to 98%.

By increasing the temperature of the t-filX- ture of ferrous chlorid liquor and carbonate the same time forcing air I form magnetic oxid of 11011 (FY3 0 This is washed to free it from soluble salts-is then filtered and caltuned.

by this process I claim an additional ad vantage to the present process of inalnng red oxid from ferric hydrate-as I have t l I I I l I I l l i I 1 temperature in the oxidation process, as by Varying the temperatures I obtain precipitates, which when calcined will give shades of oxid of iron ranging from crimson red to deep Indian red. The higher the tempo"- ature during the process of oxidation, the deeper the resultant shade of oxid. will be when calcined.

What I claim as my invention and desire to protect by Letters Patent is:*

"he process of preparing ferric hydrate Fe (OH by treating ferrous chlorid FeCl with calcium carbonate (ltd/0 and subsequently forcing carbon dioxid C0 and air tl'ierethrougl'i substantially as described.

2. The process of preparing ferric oxid F0 0 which consists in treating a waste or other liquor containing a solution of 1 81- rous chlorid FeCl with calcium carbonate CaCO and. blowing carbon dioxid CO and air theretl'irongh to precipitate ferrous carbonate FeCO and oxidize the latter into ferric hydrate FeJOH) and subsequently calcining the ferric hydrate to drive oti the water substantially as described.

In testimony whereof I have hereunto set my hand in presence of two subscribing witncsses.

JOHN GILL. Witnesses I OWDEN OBnrnrz,

ARRY Bixnmnw'mui. 

